condition mean min max ZT0-3 8.134481666666666 7.253585 8.67697 ZT4-7 8.453885 8.453885 8.453885 ZT8-11 5.37762 5.37762 5.37762 ZT12-15 5.58769 4.8994 6.27598 ZT16-19 5.75155 5.75155 5.75155 ZT20-23 8.37133 8.37133 8.37133